1. Field of the Invention
The present invention relates to a method of attaching an electronic device such as a distributor or a signal amplifier to a coaxial cable used for cable communications or cable broadcasting such as CATVs (community antenna televisions), and to an electronic device suitable for being connected to a coaxial cable by the method.
2. Description of the Prior Art
Conventional cable broadcasting has been utilized for providing telecasting or textual information to people in areas where radio waves can not be received or to subscribers such as hotels. In addition to this utilization just for providing broadcasting such as CATVs, it is expected to utilize cable transmission as an integral information system capable of duplex transmission with multiple functions of, for example, telephone, facsimile, internet, CATV, ticket reservations and the like.
Electronic devices such as modems, adaptors for communication equipment and the like are adapted to be supplied with power through associated coaxial cables transmitting video or audio signals therethrough so that information systems can remain available even when commercial power failure occurs. It is now possible that even telephone systems are kept available during the failure of commercial power.
FIG. 1 shows a coaxial cable 2 attached with electronic devices 1 such as a signal amplifier and a distributor. Before the commencement of cable broadcasting service or cable communication service, coaxial cables are disposed in place and then attached with a distributor having an output terminal to be connected to a lead-in wire of a user house. If video or audio information signals do not reach a predetermined level, problems of unclear images, inaccurate signal transmission and the like occur. Accordingly, signal amplifiers are attached to the coaxial cable at predetermined intervals so as to increase the signal level to above the predetermined level.
Initially, an area consisting of, for example, one hundred houses is provided with such coaxial cable equipment capable of servicing for sixty houses, because it is rare that all the families in such area wish to use for example cable broadcasting services from the beginning.
Accordingly, when the demand for such services increases, electronic devices such as signal amplifiers or distributors need to be added as required.
To add such electronic devices, the coaxial cable is once cut off at a portion to which any required electronic device is to be attached. Subsequently, a connector is attached to each of the cut ends of the cable and then connected to the electronic device.
However, such attaching work causes breakage of power and signal supply to houses located downstream of the cut portion of the cable, thereby causing users in the downstream houses to become incapable of making use of any service such as cable broadcasting. Further, it inconveniently causes such users to become incapable of using telephones where power is supplied to their associated modems or like devices through the coaxial cable.
Further, an increase in part count due to addition of connectors or a like devices causes reflection of signals to occur more likely at connecting portions, resulting in degradation of electric characteristics such as standing wave ratio and the like.
Moreover, such attaching work usually includes many processes such as cutting the coaxial cable and attaching connectors thereto at high elevations and hence requires a longer time. For the purpose of avoiding accidents of falling from the workplace, it is desirable that such processes at high elevations be completed in a shorter time.
It is therefore an object of the present invention to provide a method of attaching an electronic device such as a signal amplifier or a distributor to a coaxial cable which eliminates the necessity of cutting the coaxial cable in attaching such electronic devices to the coaxial cable and which enables such attaching work in a shorter time without degrading the mechanical strength and electric characteristics of the coaxial cable.
It is another object of the present invention to provide an electronic device which is capable of being attached to a coaxial cable by the method.